Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders associated with overweight and obesity. It affects 5-10% of adolescent girls and women of reproductive age. Diagnosis requires two of the following three symptoms 1) oligo- or anovulation, 2) clinical and/or biochemical signs of excess androgens, or 3) polycystic ovaries. Insulin resistance is a cardinal feature of PCOS given that the majority of women are overweight or obese. Other metabolic derangements including diabetes and hyperlipidemia are also common. PCOS has recently been shown to be associated with obstructive sleep apnea syndrome (OSAS) that may further lead to significant cardiovascular and neurocognitive deficits. However, studies of the mechanisms leading to OSAS in women or adolescent girls with PCOS are lacking. The overarching goal of this proposal is to determine the anatomical and functional risk factors for OSAS in girls with PCOS aged 13-18 years. We will use state-of-the-art techniques for image acquisition, processing and analysis to develop a functional model of the upper airway and surrounding tissues. Such a model will predict the severity of OSAS and enable the development of treatment strategies. We foresee that tools developed in this study will be applied to other phenotypes of OSAS in both children and adults. (End of Abstract)